Susceptibility of four species of turfgrass-infesting scarabs (Coleoptera: Scarabaeidae) to Bacillus thuringiensis serovar japonensis strain Buibui

Bacillus thuringiensis serovar japonensis strain Buibui experimental formulations containing Cry8Cal delta-endotoxin were evaluated in the field for the control of oriental beetle, Anomala orientalis Waterhouse; Japanese beetle, Popillia japonica Newman; Asiatic garden beetle, Maladera castanea (Arrow); and European chafer, Rhizotrogus majalis (Razoumowsky) larvae infesting turfgrasses. In 17 fall applications, control of A. orientalis and P. japonica was achieved at rates as low as 100 g of toxin per ha; however, rates of 301 or 593 g/ha were consistently more effective. A. orientalis larvae were the most susceptible followed by P. japonica, R. majalis, and M. castanea. Two spring applications of 120 g of toxin per ha were not effective against oriental or Japanese beetles.     

Does host range influence susceptibility of herbivorous insects to non-host plant proteinase inhibitors?

We examined the influence of proteinase inhibitors on digestive enzymes and development of oriental beetle,Exomala orientalis Waterhouse, European chafer,Rhizotrogus majalis (Razoumowsky),Phyllophaga white grub,Phyllophaga anxia (LeConte), cranberry root grub,Lichnanthe vulpina (Hentz), Japanese beetle,Popillia japonica Newman, Asiatic garden beetle, Maladera castanea (Arrow) (Coleoptera: Scarabaeidae), and the black cutworm,Agrotis ipsilon (Rottemburg) (Lepidoptera: Noctuidae). We demonstrated that all species within our test group had alkaline midguts that contained proteinase activity that could be inhibited,in vitro with serine proteinase inhibitors. Our data suggests that host range may influence the susceptibility to non-host inhibitors. Chronic ingestion of the serine proteinase inhibitor, Kunitz-soybean trypsin inhibitor (STI), significantly reduced proteolytic activityin vivo in those species with relatively specialized feeding habits (i.e., cranberry root grub, Japanese beetle, Asiatic garden beetle, and black cutworm). Chronic ingestion of STI also resulted in reduced larval growth and delayed pupation for black cutworm, and elevated larval mortality for Japanese beetle. However, chronic ingestion of STI did not influence larval survival for those species with relatively generalized feeding habits (i.e., oriental beetle, European chafer). Based on these results, we propose mechanistically-based criteria for selecting proteinase inhibitors for phytochemical defense against herbivorous insects.     

Incidence of turf-damaging white grubs (Coleoptera: Scarabaeidae) and associated pathogens and parasitoids on Kentucky golf courses

Root-feeding grubs (Coleoptera: Scarabaeidae) were sampled from damaged areas of 61 irrigated roughs on 32 Kentucky golf courses to determine species composition and natural enemy incidence, the first such survey in the United States' transitional turfgrass climatic zone. Masked chafers (Cyclocephala lurida Bland and C. borealis Arrow) and Japanese beetle (Popillia japonica Newman) accounted for ≈73 and 26% of grubs found in an autumn survey, with Cyclocephala spp. predominating at most sites, although mixed infestations were common. Only a few Phyllophaga spp., and no exotic species other than P. japonica were found. Cyclocephala spp. also predominated in seasonal and statewide surveys regardless of whether a course had cool- or warm-season grass fairways. Pathogenic bacteria, Paenibacillus and Serratia spp., and the autumn-active parasitoid Tiphia pygidialis Allen were the main enemies associated with Cyclocephala spp. Predominant enemies of P. japonica were Paenibacillus, Serratia, and Metarhizium spp. in autumn, and eugregarines, Stictospora sp. (probably S. villani Hays and Clopton) and Tiphia vernalis Rohwer in spring. Entomopathogenic nematodes and the microsporidian Ovavesicula popilliae Andreadis & Hanula were nearly absent in our samples. No predictive relationships were found between soil parameters and proportionate abundance of Cyclocephala or P. japonica, or with natural enemy incidence at particular sites. Although incidence of individual enemies was generally low (<20%; often <5%) in these point-in-time surveys, collectively and over their hosts' prolonged development they may take a significant toll on grub populations.     

Synergism of Entomopathogenic Nematodes and Imidacloprid against White Grubs: Greenhouse and Field Evaluation

In previous greenhouse studies, the insecticide imidacloprid and the entomopathogenic nematode Heterorhabditis bacteriophora Poinar interacted synergistically against third instars of the masked chafers Cyclocephala hirta LeConte and C. pasadenae Casey (Coleoptera: Scarabaeidae). We tested this interaction for two additional nematode species and three additional scarab species under field conditions. In greenhouse tests, H. bacteriophora and Steinernema glaseri (Steiner) interacted synergistically against third instars of the Japanese beetle, Popillia japonica Newman, the oriental beetle, Exomala orientalis Waterhouse, and the masked chafers Cyclocephala borealis Arrow, C. pasadenae, and C. hirta. The degree of interaction varied with nematode species. The strongest synergism occurred between imidacloprid and S. glaseri. Synergism between imidacloprid and H. bacteriophora was weaker and the interaction was not always significant. Combinations of imidacloprid and S. kushidai Mamiya only resulted in additive mortality. The synergistic interaction was also observed in field trials but the results were more variable than those under greenhouse conditions. The combination of nematodes and imidacloprid could be used for curative treatments of white grub infestations, especially against scarab species that are less susceptible to nematodes and/or imidacloprid. This combination has a low environmental impact and high compatibility with natural biological control of turfgrass insects. The possible roles of these combinations in augmentative control approaches are discussed.     

Evaluation of two prototype traps and existing trap designs for captures of Japanese beetles (Coleoptera: Scarabaeidae)

Two prototype trap designs and four other trap designs currently on the market were evaluated for capture of Japanese beetles, Popillia japonica Newman. The standard Japanese beetle trap manufactured by Trece (Palo Alto, CA) and a prototype trap captured consistently more beetles than other trap designs tested. Traps that used a bag for collection of beetles were not as effective because beetles were able to escape through the holes made for drainage. The new trap design allows traps to be transported more easily and stored in a smaller area because of the collapsible design. This is a significant improvement for states that use thousands of traps for monitoring Japanese beetles.     

Comparison of scarab grub populations and associated pathogens and parasitoids in warm- or cool-season grasses used on transitional zone golf courses

Seven different turfgrass species or mixes used on golf courses in the United States' transitional climatic zone were maintained as randomized and replicated plots in separate stands mowed at fairway (1.6 cm) or rough (6.4 cm) cutting heights and sampled in autumn to assess the density and species composition of scarab grubs; incidence of disease and parasitism thereof; and extent of turf damage from foraging insectivorous skunks, Mephitis mephitis. Influence of grass species on parasitism by spring or autumn-active tiphiid wasps was further assessed on implanted grubs in open enclosures. Masked chafers (Cyclocephala spp.) were three-fold more abundant than Japanese beetle, Popillia japonica Newman, grubs in plots of Zoysia and Cynodon sp. mowed at fairway height, and P. japonica were five-fold more abundant than masked chafer grubs in cool-season turf plots mowed at rough height. Phyllophaga spp. accounted for <1% of grubs in the samples. Milky disease bacteria (Paenibacillus sp.) were the predominant pathogens of Cyclocephala spp., followed by Serratia sp. bacteria and gregarines (Stictospora cf. villani). Cyclocephala grub densities, milky disease incidence (25%), and parasitism by the native tiphiid Tiphia pygidialis Alien (10-12%) were especially high in zoysiagrass. Japanese beetle grubs were infected by Paenibacillus, Serratia, Stictospora, and microsporidia (Ovavesicula sp.), but incidence of individual pathogens was relatively low (<6%) and similar among grasses within each stand. Few nematode-infected grubs were found. Skunk damage was mainly in the cool-season fairway-height grasses, probably reflecting difficulty in foraging in the much tougher stolons and rhizomes of the warm season turfgrasses. The degree of natural suppression of scarab grubs provided by endemic pathogens or parasitoids is unlikely to be compromised by the grass species used on a particular site.     

Spatial and temporal distribution of endemic and released entomopathogenic nematode populations in turfgrass

Entomopathogenic nematodes (Rhabdita: Heterorhabditidae and Steinernematidae) have been effective as inundative biological control agents of scarab larvae (Coleoptera: Scarabaeidae) in turfgrass. Entomopathogenic nematodes also occur naturally in turfgrass and endemic or inoculated populations may be able to provide effective long-term control. Variation in Heterorhabditis bacteriophora and Steinernema carpocapsae spatial and temporal distribution along transects placed at different turfgrass sites in central New Jersey, USA, was investigated. H. bacteriophora tended to be recovered from fewer sections in a transect than S. carpocapsae, but the two species, overall, did not differ in patchiness of distribution. In one transect with a H. bacteriophora population S. feltiae was also recovered, but the two populations seldom overlapped spatially. In transects with adequate scarab larvae density for analysis, H. bacteriophora density and Popillia japonica larvae density were inversely correlated. This suggests that endemic H. bacteriophora populations may suppress P. japonica populations. In one transect, an epizootic of H. bacteriophora in an undetermined host may have occurred. Edaphic factors were relatively uniform along transects and were, at most, weakly correlated with nematode recovery. Uniform inoculative releases of H. bacteriophora tended to return to patterns of distribution typical of endemic populations.     

Impact of four insecticides on Japanese beetle (Coleoptera: Scarabaeidae) egg predators and white grubs in turfgrass

Field experiments were conducted to measure the effects of four commonly used turfgrass insecticides (isofenphos, diazinon, imidacloprid, halofenozide) on white grubs (Coleoptera: Scarabaeidae) and ant predators of white grub eggs. Ant populations were measured over time with canned tuna, whereas predation by the ants was measured with artificially placed Japanese beetle, Popillia japonica Newman, eggs. The effectiveness of each insecticide at controlling Japanese beetle grubs, when applied at different times during the growing season, also was measured. Isofenphos and diazinon significantly reduced both ant numbers and white grub egg predation, whereas imidacloprid and one halofenozide treatment did not significantly impact either measurement. A second halofenozide treatment significantly reduced white grub egg predation. Isofenphos and diazinon were ineffective at controlling Japanese beetle grubs when applied in June but were highly efficacious when applied in August. Evidence of enhanced biodegradation was found in plots that received both June and August applications of diazinon. Both June and August applications of imidacloprid and halofenozide provided good control of white grubs.     

Revision of the genus Stictospora and description of Stictospora villani, n. sp. (Apicomplexa: Eugregarinida: Actinocephalidae) from larvae of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), in Michigan

Stictospora villani n. sp. is described from larvae of the Japanese beetle Popillia japonica (Coleoptera: Scarabaeidae) from southern Michigan. Stictospora villani is distinguished from known species of the genus by differences in gamont size and by structural details of the epimerite. In general, S. villani is smaller than other known species of the genus and possesses an epimerite with a margin of 20-24 sympetalous, pendulate, narrowly to very narrowly elliptoid lamina. Previously described species are characterized by epimerites with notably fewer marginal lamina. A heretofore unrecognized protistan is diagnosed from the coelomic fat bodies and tentatively placed within the Neogregarinorida. We conclude that previous workers have mistaken this neogregarine for the gametocyst and oocyst of Stictospora, which are described in this study for the first time. The generic diagnosis of Stictospora is revised to encompass the epimeritic variation of its constituent species and to correctly reflect the morphology of the oocyst.     

Drench treatments for management of larval Japanese beetle (Coleoptera: Scarabaeidae) in field-grown balled and burlapped nursery plants

Insecticide drenches were applied to postharvest field-grown nursery plants harvested as 60-cm-diameter balled and burlapped (B&B) root balls for controlling third instars of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae). Bifenthrin, chlorpyrifos, lambda-cyhalothrin, and thiamethoxam were drench-applied in fall and spring tests at volumes of runoff (1X; approximately equal 2.57 liters per drench per root ball) or twice runoff (2X). Tests also examined consecutive drenches (two, four, or six) and B&B rotation between drenches. Fall-applied drenches did not meet the Domestic Japanese Beetle Harmonization Plan (DJHP) standards of < or =1 grub and ranged from 0 to 90% control. However, most fall-applied drenches significantly reduced grub numbers relative to the untreated root balls. Spring-applied drenches were more effective than fall drenches: chlorpyrifos treatments gave 94-100% control, whereas other spring-applied treatments were less consistent, including thiamethoxam (83-100% control) and bifenthrin (61-100% control). Lambda-cyhalothrin was not effective. A higher drench volume (2X) did not significantly improve treatment efficacy; however, grub numbers decreased as the number of drenches increased for fall-applied chlorpyrifos and thiamethoxam and spring-applied bifenthrin. Rotation of root balls significantly reduced grub numbers compared with nonrotated treatments for fall-applied chlorpyrifos (six drenches) and bifenthrin (two or six drenches), but these treatments did not meet DJHP standards. The study indicates chlorpyrifos, bifenthrin, and thiamethoxam drenches can control Japanese beetle in the spring and may provide a new postharvest option to certify B&B plants for Japanese beetle.     

Japanese beetle lures used alone or combined with structurally related chemicals to trap NE China scarabs (Coleoptera: Scarabaeidae)

Scarab beetles are agriculturally important worldwide, and as adults or larvae they may cause damage to the leaves, flowers, fruit, and roots of crops. Previous international studies showed that Japanese beetle (Popillia japonica, Newman) lures, and structurally related chemicals, can attract numerous scarabs. Based on those studies, season-long trials in grape, cabbage, corn and soybean fields were conducted in 2012–2013 in NE China. Tests determined the attractiveness of the Japanese beetle floral lure (phenethyl propionate:eugenol:geraniol, 3:7:3) and sex attractant (Japonilure), alone, combined, or in a mixture with either (Z)-3-hexen-1-ol, anethole = 1-methoxy-4-propenyl benzene or benzyl alcohol, to local Coleoptera. Furthermore, control efficacies based on leaf, ear, and silk damage, as well as reductions of adults on plants, and overwintering larvae, were also determined. Eleven scarab species, and four non-scarab species, were captured. The addition of other chemicals increased the attractiveness of the two Japanese beetle lures to scarabs such as Potosia brevitarsis (Lewis), Oxycetonia jecunda Faldermann, Holotrichia diomphalia Bates et al., Popillia quadriguttata (Fabricius), Maladera verticalis (Fairmaire), and Metabolus impressifrons Fairmaire, and the chrysomelid beetle Chrysomela populi L. The floral lure, and floral lure plus Japonilure baited traps resulted in > 80% overwintering larvae and adult reductions in corn and cabbage fields, whereas the Japonilure traps gave similar results in the soybean fields. This indicates that the commercial Japanese beetle lure combination can be recommended for use by the Chinese farmers in the corn or soybean fields, and that the related chemicals can be used to increase the attractiveness of the Japanese beetle lures.     

Ultrastructure of pheromone-detecting sensillum placodeum of the Japanese beetle, Popillia japonica Newmann (Coleoptera: Scarabaeidae)

The pheromone-detecting sensilla placodea are significantly more numerous than other sensory structures in the antennae of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae). Their abundance in males is nearly twice of that in females, showing a clear sexual dimorphism. Externally, they have a tortoise shell-like round cuticular plate containing a few polygonal plates separated by narrow ridges. Internally, they house two long dendrites that branch and terminate near fine cuticular pores. They have a system of two bipolar neurons accompanied by three enveloping cells, resembling sensilla trichodea in moths. The conspicuous difference with the latter is that the sensillum-lymph cavity near the outer cuticle is funnel-shaped, into which the tormogen cell projects numerous microvilli whose tips approach the terminal branches of the dendrites.     

Rainfastness and residual activity of insecticides to control Japanese beetle (Coleoptera: scarabaeidae) in Grapes

Field-based bioassays and residue profile analysis were used to determine the relative toxicity, rainfastness, and field degradation over time of five insecticides from five insecticide classes on adult Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), in grapes, Vitis labrusca L. Bioassays assessed Japanese beetle condition as alive, knockdown, or immobile when exposed for 24 h or 7-d field-aged residues of phosmet, carbaryl, bifenthrin, thiamethoxam, or indoxacarb after 0, 12.7, or 25.4 mm of rain had been simulated. We found that the two most toxic insecticides to Japanese beetle were phosmet and carbaryl, followed by bifenthrin, thiamethoxam, and then indoxacarb. The efficacy of phosmet decreased because of rainfall, but not because of field aging. The efficacy of carbaryl decreased because of rainfall and field aging. The efficacies of bifenthrin and thiamethoxam were not affected by rainfall but decreased because of field aging. The efficacy of indoxacarb was not affected by rainfall or field aging. This study will help vineyard managers make informed decisions on when reapplications of insecticides are needed with the aim of improving integrated pest management programs.     

Spatial density‐dependent parasitism and specificity in the robber fly Mallophora ruficauda (Diptera: Asilidae)

The density‐dependence in parasitism by the robber fly Mallophora ruficauda (Diptera: Asilidae) on scarab beetle larvae (Coleoptera: Scarabaeidae) populations was studied in the present research. Mallophora ruficauda is a pestiferous species common in the open grasslands of the Pampas region of South America. Adults are predators of insects and larvae are solitary parasitoids of third instar larvae of several species of scarab beetle (Coleoptera: Scarabaeidae). In contrast with most studied host‐parasitoid interactions, host searching by M. ruficauda is carried out by both larvae and adults. Typically, robber fly females lay eggs on tall grasses from where larvae drop to the ground, and attack hosts which are buried in the soil. We carried out our study at two spatial scales close to 14 apiaries located in the provinces of Buenos Aires and Entre Ríos (Argentina). We found that parasitism is density‐independent at the larger spatial scale and inversely density‐dependent at the smaller one. We also found that M. ruficauda selects Cyclocephala signaticollis among several scarab beetle species. Specificity is observed both at large and small spatial scales. We discuss the implications of both host specificity and host searching behaviour on the observed parasitism patterns.     

Effect of white grub developmental stage on susceptibility to entomopathogenic nematodes

The pathogenicity of the entomopathogenic nematodes Heterorhabditis bacteriophora Poinar and Steinernema scarabaei Stock & Koppenh?fer against different developmental stages of the Japanese beetle, Popillia japonica Newman, and the oriental beetle, Anomala (=Exomala) orientalis Waterhouse, were studied under laboratory conditions. The efficacy of S. scarabaei did not differ between second and third instars in P. japonica or A. orientalis or between small (young) and large (older) third instars in A. orientalis. However, H. bacteriophora efficacy decreased from first over second to third instar and also from small third instars to large third instars in A. orientalis but did not differ significantly between P. japonica larval stages. Once A. orientalis third instars had purged their intestines in preparation for pupation, no significant mortality by S. scarabaei and H. bacteriophora was observed. In contrast, P. japonica susceptibility to both nematode species gradually decreased from stage to stage from actively feeding third instars to pupae. In two additional experiments, we found no difference in Steinernema glaseri (Steiner) susceptibility between second and third instars of A. orientalis but an increase in S. scarabaei susceptibility from the second to third instar of Asiatic garden beetle, Maladera castanea (Arrow). Our observations combined with those of previous studies with other nematode and white grub species show that nematode efficacy against white grub developmental stages varies with white grub and nematodes species, and no generalization can be made.     

An Efficient Pit-light Trap to Study Beetle Diversity

A new, highly efficient pit-light trap is described and results of experiments on its efficacy that were carried out in various types of forests are presented. The Luminoc® insect trap is made of two parts: a 1-L collection container inserted into the ground and an upper container which houses a 6-V lantern battery and a circuit for electronic control of a 1.8-W miniature fluorescent tube. A cover is fixed under the upper container to prevent rainwater from entering the collection container. The pit-light trap caught significantly more specimens, species and families of Coleoptera than passive pitfall traps. Many species of common families, such as Carabidae, Cantharidae, Curculionidae, Elateridae, Pyrochroidae, Scarabaeidae, Silphidae and Tenebrionidae were mainly caught in pit-light traps. Several species of uncommon families such as Byrrhidae, Melandryidae, Scraptiidae, Stenotrachelidae and Throscidae were caught only in pit-light traps. The light source increases the sampling area of a trap to include many micro-habitats, which makes pit-light traps more efficient tools that provide less variable results than the passive pitfall traps. The use of only three pit-light traps allows the capture of three times more 'abundant and common' species than any number of passive pitfall traps could provide. Thus, the pit-light trap allows an easier and more accurate characterization of Coleoptera communities than the passive pitfall trap. Because of its high efficacy, the pit-light trap should be considered as a standard tool to study, monitor and inventory beetle diversity.     

Distribution and dynamics of Japanese beetles along the Indianapolis Airport perimeter and the influence of land use on trap catch

As part of a program to minimize the accidental transportation of Japanese beetles (Popillia japonica) through cargo aircraft to areas where they are not established, a 4-yr trapping project was initiated to study the relative distribution and dynamics of the beetles along a trap line around the Indianapolis International Airport. Land use influence on beetle abundance (trap catch) was assessed using a geographic information system. Trap catch was consistently high in some locations and low in others. In general, high trap catches occurred near agronomic land planted with corn or soybeans, which are both preferred hosts of adult beetles. Low trap catches generally occurred in areas lacking preferred host plants. The amount of agronomic land within 500 m of the traps was always positively correlated with trap catch. Average trap catches were highly correlated by location from year to year, indicating stability of the relative distribution of the beetles along the trap line. Because high trap catches consistently occurred in the same locations, it can be inferred that trapping can be an effective method to monitor Japanese beetle populations. Taking airport-owned agronomic land out of corn and soybean production near the cargo terminals may reduce beetle activity in these areas.     

Effects of pesticide applications and cultural controls on efficacy of control for adult Japanese beetles (Coleoptera: Scarabaeidae) on roses

Cultural and chemical controls were evaluated to determine their ability to deter feeding by Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), on floribunda type roses, Rosa 'Acadia Sunrise'. Roses were arranged in field plots and exposed to resident adult beetle populations. Cultural controls were designed to block the feeding-induced aggregation response by manually removing beetles and/ or damaged blooms from rose plants. Azadirachtin, carbaryl, and imidacloprid were evaluated in field and laboratory trials. In no-choice laboratory assays, foliar applications of azadirachtin caused low rates of morbidity to adult beetles and were unable to deter feeding. Foliar-applied carbaryl and soil-applied imidacloprid caused high rates of morbidity and reduced feeding injury. In the field, foliar sprays of azadirachtin and carbaryl, deterred feeding on foliage under low beetle pressure (maximum of 29% defoliation in untreated controls), when applied weekly after first beetle flight or every 2 wk after 5% injury was reached. A single foliar application of these materials at the 5% injury level did not significantly reduce peak defoliation. Soil applications of imidacloprid also deterred foliar feeding in the field. Blooms were more difficult to protect with both foliar- and soil-applied insecticides with only weekly application of foliar insecticides providing significant reductions in bloom injury. Removing beetles and/or blooms provided marginally greater reductions in leaf and flower injury. This suggests that blocking the feeding-induced aggregation response of Japanese beetles can provide only modest levels of control in roses where both flowers and feeding-induced volatiles recruit beetles to plants.     

A comparison of dung beetle (Coleoptera: Scarabaeidae) attraction to native and exotic mammal dung

Although the preference of dung beetles (Coleoptera: Scarabaeidae) for specific types and conditions of dung has been given substantial attention, little has been done to investigate the potential effects of exotic mammal introduction for game farms or rewilding projects. We used pitfall traps baited with various native and exotic herbivore, carnivore, and omnivore dung to evaluate dung beetle preference in the Great Plains of North America. Additionally, we analyzed of the nutrient quality of each dung type. In total, 9,089 dung beetles from 15 species were captured in 2 yr of sampling. We found significant differences (P < 0.05) in mean dung beetle capture among omnivore, herbivore, and carnivore dung, as well as differences in individual species preference for dung type. Omnivore dung was the most attractive with chimpanzee and human dung having the highest mean capture (291.1 ± 27.6 and 287.5 ± 28.5 respectively). Carrion also was highly attractive with a mean of 231.9 ± 20.6 beetles per trap (N = 8). Our results suggest definitive local preference of carrion in Phanaeus vindex Macleay and Onthophagus hecate (Panzer), while the congener, O. pennsylvanicus (Harold), was rarely captured in carrion and highly preferred omnivore dung. Preference for a specific bait type does not appear to be correlated with dung quality, mammalian diet, or origin of mammal. Results suggest niche segregation by dung type among dung beetle species.     

Biological control agents for white grubs (Coleoptera: Scarabaeidae) in anticipation of the establishment of the Japanese beetle in California

We tested biological control agents for the control of 3rd-instar scarab turfgrass pests, both for the masked chafer Cyclocephala hirta LeConte and the Japanese beetle, Popillia japonica Newman. The former species is endemic in California whereas the latter, although not yet established, constitutes a permanent serious threat to agriculture and horticulture in California. We conducted experiments using C. hirta in California and P. japonica in New Jersey. A field trial conducted in 2 different California turfgrass sites compared the field persistence in the absence of hosts of Bacillus thuringiensis Berliner subspecies japonensis Buibui strain, the milky disease bacterium, Paenibacillus (=Bacillus) popilliae (Dutky), and the entomopathogenic nematodes Steinernema kushidai Mamiya and Heterorhabditis bacteriophora Poinar to that of the organophosphate diazinon. Soil samples taken 0-70 d after applications were bio-assayed with P. japonica. Only diazinon and the entomopathogenic nematode S. kushidai caused substantial mortality and S. kushidai activity persisted significantly longer than diazinon activity. In greenhouse experiments, combinations of entomopathogenic nematode species usually resulted in additive mortality of scarab larvae. Combinations of S. kushidai and diazinon also resulted in additive mortality. In field trials, the efficacy of H. bacteriophora and especially S. kushidai and S. glaseri, was comparable to that of diazinon over 14-18 d. However, it is likely that at least S. kushidai would have outperformed diazinon over an extended period because of its longer persistence and potential for recycling in the hosts. S. kushidai, should it become commercially available, deserves further examination as an alternative to chemical white grub control especially as a highly compatible component of sustainable turfgrass management.